- A two-lobed endocrine gland found in all vertebrates, located in front of and on either side of the trachea in human beings, and producing various hormones, such as triiodothyronine and calcitonin.甲状腺：所有脊椎动物所共有的一种分成两叶的内分泌腺，在人体内位于气管的前部和两侧，能生成三碘甲腺氨酸和降钙素等各种激素